Amplifier power supply



y 1933- l. KIRSTAEDTER 1,917,722

AMPLIFIER'POWER SUPPLY Filed July 18, 1930 INVENTOR IRMFRED KIRSTAEDTERATTORNEY Patented July 11, 1933 barren- STATES PATENT OFFICE IRMERIEDKras'mnnrnn, or BERLIN, ens-Many, Assrsnoia-tro SIEMENS & HALsxE,AKTIENGESELLSCHAFT, or SIEMENSSTAIDT nnnnniinnin, GERMANY, A conronnTION E GERMANY AMPLIFIER -rownn surrLY Application filed. July 18, 1930,Serial No. 468,806, and in Germany June 17, 1929. Y

The present invention relates to apparatus for amplification andrectification of signal currents, supplied with energy from networks. v

Amplifiers which are supplied from a supply line, or power network, andafter having been connected with the latter, require a certain length oftime until the cathodes of the amplifier tubes have been heated to thetemperature where electron emission is initiated. This phenomenonbecomes partic.u

larly noticeable with tubes employing indirectly heated cathodes. It isalso noticeable in tubes employing directly heated cathodes, if thecathode current is derived from a rectifier also taking a certain lengthof time for getting started. Thesame condition has been observed indevices including low-pass filters designed to smooth the direct currentand rid itof straycomponents. But, this defect is particularly apparentand serious, in the case of indirectly heated tubes employed in anamplifier utilized as part of an order, or safety signal, equip ment.Such order, or control, systems consist, for instance, of a microphoneat the transmitter end and a loudspeaker for rendering the orders orsignals, audible, the network supply means, or power pack, beinginsorted between these two parts of the equip ment. In order to secureimmediate operatio it is essential to permanently maintain the amplifiercircuit, and this would involve a relatively great wear and tear intubes, and excessive current consumption.

Now, according to the present invention practically instantaneousoperation is insured with considerably reduced current consumption andtube depreciation, by employing means adapted to reduce the cathodetemperature for the time the installation is held in readiness foroperation. A device of this kind may have the form ofa switch insertedin the filament circuit which in one of its positions cuts a resistancein the circuit. It is preferable to provide the switch with three stagesor steps, one step each being for complete cutting in, and out, ofcircuit, while the third position cuts the resistance in the filamentcircuit during the periods where the device is held in readiness. Inthis manner it is possible to pro-heat the amplifier tube cathodes, bymeans of the series resistance, to a point where it is ready for actualoperation within a few seconds time, after connection. M

' The novel features which I believe to be characteristic of myinvention are set forth with particularity in the appended claims, theinvention itself, however, as to both its organization and. method ofoperation will best be understood by reference to the fola power pack,ornetwork supply. The amplifier V is connected with the alternatingcurrent supply line N. through two paths comprising the switch S and theresistance R.

The switch is illustratedin further detail in Fig. 2/

In position A, the power pack amplifier V V ll hilc I have indicated anddescribed one arrangement for carrying my invention'into effect, it willbe apparent to one skilled in the art that my invention is by no meanslimited.

to the particular organization shown and described, but that manymodifications may be made without departing from the scope of myinvention set forth in the appended claims.

What I claim is: y

1. In an amplifier circuit which includes at least one electrondischarge relay provided with a cathode of the type having an inherentdelay characteristic of such duration as to make appreciable the lengthof time required for the relay to assume normal operation after theapplication of energizing potentials thereto, a cathode energizingcircuit including a source of current for supplying electrical energy ata voltage best adapted for normal operation of the electron relay whennormal operation thereof is desired, means adapted to be connected tothe cathode energizing circuit for reducing the voltage of the energysupplied to the cathode energizing circuit from said source to a valueinsufficient for normal operation of the relay device but sufiicient tomaintain the cathode at such a state of energization that it will assumenormal operation characteristics substantially contemporaneous with'theapplication oi normal voltage values to the circuit, said meanscomprising a fixed resistance element adapted to be placed in and out ofthe cathode energizing circuit by means comprising aswitch having twosets of contacts and a contact operating element, said contact operatingelement being adapted to close either set of contacts, means forconnecting the cathode energizing circuit directly across the sourcewhen one of said sets of contacts is closed by said element so as toimpress the normal operatingvoltage across said circuit, and means forconnecting the source and said cathode energizing circuit through-theresistance device when the other set of contacts is closed by saidelement so as to impress the reduced voltage across the circuit.

2. In an amplifier circuit which includes at least one electrondischarge relay provided with an indirectly heated cathode, anenergizing circuit for said cathode including a source of currentadapted to supply electrical energy to said energizing circuit at avoltage best adapted for normal operation of the electron relay, meanscomprising an impedance element adapted to be'inciuded in the cathodeenergizing circuit for reducing the voltage of the energy supplied fromsaid source to the cathode energizing circuit to an inter mediate valuesaid value being insutlicient for normal operation of the relay devicebut suilicient to maintain the cathode at such a state of energizationthat it will assume normal operation characteristics substantiallyconlemporaneously with the application of normal voltage to the cathodeenergizing circuit, and aselector device in cooperative relation withthe cathode energizing circuit for alternatively rendering the impedanceelement inoperative to control the operation of the relay during desiredperiods of normal operation of relay and rendering the impedance elementoperative to reduce the voltage of the electrical energy applied to thecathode energizing circuit to said intermediate value.

In testimony whereof I aifix my signature.

IRMFRIED KIRSTAEDTER.

